City of Charlottesville
Water Resources Protection Program
Stormwater Utility Fee Credits Manual
Your guide to reducing stormwater utility fees and protecting our City’s
water resources.
City of Charlottesville, Virginia
605 E. Main St., Charlottesville, VA 22902
www.charlottesville.org/stormwater
Stormwater Utility Credits Manual – January 2014
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City of Charlottesville
Water Resources Protection Program
Stormwater Utility Credits Manual
Table of Contents
Stormwater Overview ................................................................................................ 1
Water Resources Protection Program ........................................................................ 1
Stormwater Utility Fee ............................................................................................... 2
 What is a stormwater utility fee?
 How is the fee calculated?
 Is there anything I can do to reduce my bill?
Credit Program ........................................................................................................... 3
 What are the eligibility requirements?
 How much credit can I get?
 How do I apply?
Important Resources and Links ............................................................................... 10
Forms
Credit Application Form
Credit Calculation Form
Stormwater Management Facility Inspection Form
Stormwater Utility Credits Manual – January 2014
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Stormwater Overview
Everyone in Charlottesville is affected by stormwater! Stormwater is water that flows over
our yards, streets, buildings, parking lots, and other surfaces when it rains or snows. When the
land was covered by forests, most of this water soaked into the ground. Today, about one third
of the City is covered with hard (impervious) surfaces. When rain falls on these surfaces, the
water cannot infiltrate into the ground. Instead, it runs
off as stormwater into a system of drains, ditches, and
pipes. In all, the City is responsible for managing
over 56 miles of stormwater pipe and 4,200
stormwater structures!
When stormwater flows over parking lots, lawns, and
streets it picks up pollutants such as oil, grease, heavy
metals, pesticides, fertilizers, sediment, trash, debris,
and pet waste. These pollutants flow directly into our
local creeks, streams, and the Rivanna River before
ultimately reaching the Chesapeake Bay. As a result,
many of our streams have been designated as
“impaired” by the Virginia Department of
Environmental Quality. State and federal law makes
the City responsible for developing and implementing
plans to restore these impaired waterways.
In addition, since less stormwater soaks into the
ground, it can accumulate and lead to drainage issues.
Increased stormwater flow also causes stream bank
erosion, which threatens water quality and private
property. Much of the City’s stormwater infrastructure
was installed in the 1950s and 1960s and is now old
and in need of repair, which also contributes to these
problems.
Stream bank erosion caused by
increased stormwater flows.
Uncontrolled stormwater can result
in drainage issues and degraded
water quality.
Water Resources Protection Program
Over the past few years the City has been working hard to develop solutions to local water
resources challenges. A Water Resources Protection Program (WRPP) is being implemented to
address these challenges in an economically and environmentally sustainable manner. The
WRPP is designed to comply with federal and state water quality regulations, rehabilitate aging
stormwater infrastructure, implement projects to address drainage and flooding problems, and
restore degraded streams.
Stormwater Utility Credits Manual – January 2014
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Stormwater Utility Fee
What is a stormwater utility fee?
The City of Charlottesville has adopted a stormwater utility fee to provide an adequate and stable
source of funding for the WRPP. A stormwater utility fee is a fee for service based on the
amount of impervious surface area on a property (roofs, parking areas, walkways, etc.). This is
similar in concept to how the City distributes the cost for sanitary sewer and drinking water
services. Per the stormwater utility ordinance passed by City Council, impervious surface is
defined as “area covered by hard surfaces such as structures, paving, compacted gravel,
concrete, or other man-made features that prevent, restrict, or impede the downward passage of
stormwater into the underlying soil”.
This approach has several advantages. First, it fairly distributes the cost of the City’s stormwater
services across all eligible properties based on the amount of impervious surface. Second, under
State Law, the revenue from a stormwater utility must be placed in a special fund that can only
be used for stormwater management; therefore establishing a dedicated funding source to
accomplish the goals of the WRPP. Finally, State Law requires the City to provide “credits” to
property owners who have implemented stormwater management facilities to reduce their
stormwater utility fees.
How is the fee
calculated?
Since a stormwater utility is a fee for service, all
eligible properties are charged regardless of their tax
status. Each eligible property is charged in 500
square foot (SF) increments of impervious area.
These are called “billing units.” Fractions are
rounded up to the next whole unit. For example, a
property that has 2,100 square feet of impervious
cover has five billing units (2,100 / 500 = 4.2,
rounded to 5 billing units). The number of billing
units is then multiplied by the rate adopted by City
Council ($1.20 per billing unit per month).
Unimproved property (defined as a property with less
than 300 square feet of impervious cover) is not
assessed a fee.
Stormwater Utility Credits Manual – January 2014
Example Fee Calculation
 Total impervious area = 2,100 SF
 Divide by 500 SF = 4.2
 Round to the next whole number =
5 billing units (BUs)
 Multiply the number of BUs (5) by
the rate ($1.20) x 12 months for an
annual fee of $72.00
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Is there anything I can do to reduce my bill?
Yes! There are two ways for you to impact the
amount of your payment.
First, property owners can remove impervious surfaces
from their property. This will result in a direct fee
reduction if the removal of impervious surface results in
fewer billing units.
Second, the City’s Credit Program provides an
opportunity for property owners to reduce their
stormwater utility bill by operating and maintaining a
stormwater management facility.
Credit Program
A credit is a reduction to the stormwater fee that can be
pursued by a property owner if they operate and maintain
a stormwater management facility that reduces pollution,
helps to control stormwater runoff, or both. Existing
stormwater management facilities are eligible for a credit
regardless of when the facility was built as long as they
meet the applicable standards at the time of installation.
There are a wide variety of practices that can be
implemented in Charlottesville that qualify for credit,
including bioretention facilities, permeable pavement, and
green roofs, just to name a few.
The City has adopted two goals for the credit program.
First, credits should recognize the avoided cost to the City
that is provided by the ongoing operation and
maintenance of a stormwater management facility.
Second, credits should provide a mechanism for property
owners to make investments to help the City achieve the
goals of the WRPP.
Stormwater Utility Credits Manual – January 2014
Examples of practices that can
receive credit – bioretention
facility (top); cistern (middle);
permeable pavement (bottom).
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What are the eligibility requirements?
To be eligible for credit, a stormwater management facility must meet the following
criteria:
 A property owner must have installed the stormwater management facility prior to applying
for the credit and the stormwater management facility must be functioning as designed.
 A property owner must own and physically maintain all components of the facility – a
property owner who only provides aesthetic maintenance is not eligible for a credit.
 The facility must have been built in accordance with the City-recognized design standards in
place at the time of installation.
 The facility must be actively maintained so that it is functioning as designed.
 The property owner must enter into a maintenance agreement with the City that includes the
right of the City to conduct periodic inspections. The City may require that an existing
agreement be modified in order for the facility to be eligible for credit.
 An unsatisfactory inspection by City staff will result in the facility being ineligible for credit
unless corrective action is taken in the timeframe prescribed by the City.
Refer to “How do I apply?” and the Credit Application Form for additional details.
How much credit can I get?
The amount of credit depends on when the facility was built and whether it was implemented
voluntarily or as a condition of development. It is important to remember that only the
impervious area treated by the facility, and not the entire impervious area of a site, is
eligible for a credit. Credit may also be taken for voluntarily treating off-site areas that are not
currently controlled by another stormwater management facility. However, the credit will be
adjusted if the off-site property owner decides to install their own facility that treats a portion or
all of the impervious area treated by the facility receiving credit. It is recommended that a
property owner coordinate with the City prior to considering any off-site treatment options.
The maximum credit that a property owner may receive for a stormwater management facility
required as a condition of development is a 40% credit of the fee for the impervious area treated.
The maximum credit is a 100% credit of the fee for the impervious area treated by a voluntary
stormwater management facility. For voluntary treatment, the maximum credit that may be
applied to a property’s stormwater utility bill is 90% of the stormwater utility fee or 100% of the
fee minus the amount of one billing unit, whichever results in the lower bill.
Stormwater Utility Credits Manual – January 2014
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Credit Level Table
Installation Date
Condition of Development or
Voluntary
Percent Credit for Impervious Area
Treated
Pre-July 1, 2009
Either
20%
Voluntary
40% to 100%1 Depending on the Level
of Pollutant Removal – See Credit
Calculator for Post-July 1, 2009
Voluntary Facilities
Post-July 1, 2009 &
Pre-July 1, 2014
Condition of Development
30%
Post-July 1, 2014
Condition of Development
40%
Post-July 1, 2009
1. The maximum credit that may be applied to a property’s stormwater utility bill is 90% of the stormwater utility
fee or 100% of the fee minus the amount of one billing unit, whichever results in the lower bill.
Credit Calculator for Post-July 1, 2009 Voluntary Facilities
The following calculation is used to determine the credit to be given to a voluntary eligible
facility installed post-July 1, 2009. The formula was developed as a sliding scale where a facility
of minimum pollutant removal efficiency (15%) receives a 40% credit and a facility of 70% or
greater efficiency receives the maximum credit. Facility efficiency is as documented in the
Virginia Stormwater BMP Clearinghouse, the Recommendations of the Expert Panel to Define
Removal Rates for Urban Stormwater Retrofit Projects, or other state-approved guidance
documents.
(A)
(B)
(C)
(D)
(E)
Facility Phosphorus Removal Efficiency Must be 15% or Greater
Facility Phosphorus Removal Efficiency of ____% / 100 x 1.761 = _______
(B) – (0.2642) = ______
(C) / 0.0163 = ______
40% + (D) = _______ Percent Total Facility Credit (up to maximum of 100%)
1. The phosphorus pollutant loading rate for the James River Basin from the City’s municipal separate storm sewer
system (MS4) permit issued by the Virginia Department of Environmental Quality.
2. 0.264 is the result of equation (B) for a 15% Facility Efficiency ensuring that equation (D) results in a value of
zero for a 15% Facility Efficiency.
3. 0.016 is a “distribution factor” to ensure that Facility Efficiency values between 15% and 70% result in equation
(D) between 0% and 60%.
Stormwater Utility Credits Manual – January 2014
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Credit Example 1
Condition of Development (COD) Stormwater Management Facility
Total Impervious Area = 15,120 SF
15,120 SF / 500 SF = 30.24
Property Billing Units (BU) = 31
Pre-Credit Annual Fee = (31 x $1.20
per BU x 12 months) = $446.40
Impervious Area Treated
(Building Rooftop Only) = 7,980 SF
Condition of Development Credit Examples
Facility
Installation
Date
Pre-July 1,
2009
Post-July 1,
2009 &
Pre-July 1,
2014
Post-July 1,
2014
Percent
Credit
20%
30%
40%
Percent Credit x
Impervious Area
(SF) Treated
7,980 x 20% = 1,596
7,980 x 30% = 2,394
7,980 x 40% = 3,192
Stormwater Utility Credits Manual – January 2014
Adjusted
Impervious
Area
Adjusted
Billing Unit
15,120 – 1,596
= 13,524
13,524 / 500 =
27.05 = 28
BU
15,120 – 2,394
= 12,726
12,726 / 500 =
25.45 = 26
BU
15,120 – 3,192
= 11,928
11,928 / 500 =
23.86 = 24
BU
Post-Credit
Annual Fee
28 x $1.20 x
12 = $403.20
($43.20 Fee
Reduction)
26 x $1.20 x
12 = $374.40
($72.20 Fee
Reduction)
24 x $1.20 x
12 = $345.60
($100.80 Fee
Reduction)
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Credit Example 2
Voluntary and Condition of Development (COD) Stormwater
Management Facility
Total Impervious Area = 15,120 SF
15,120 SF / 500 SF = 30.24
Property Billing Units (BU) = 31
Pre-Credit Annual Fee = (31 x $1.20
per BU x 12 months) = $446.40
Impervious Area Treated by
Voluntary Facility
(Paved Play Surface) = 2,800 SF
Impervious Area Treated by COD
Facility (Building Rooftop) = 7,980 SF
Voluntary and Condition of Development Credit Example
Voluntary Facility
Installation Date
Percent Credit
Percent Credit x Impervious
Area (SF) Treated
Impervious Area
Reduction (SF)
After July 1, 2009
88.4% (see
calculation below)
2,800 x 88.4% = 2,475
2,475
Voluntary Credit Calculation (After 7/1/2009)
(A)
Facility Efficiency for Level 1 Permeable Pavement (per Virginia BMP Clearinghouse) = 59%
(B)
Facility Efficiency of 59% / 100 x 1.76 = 1.038
(C)
1.038 – 0.264 = 0.774
(D)
0.774 / 0.016 = 48.4
(E)
40% + 48.4 = 88.4% Total Facility Credit
COD Facility
Installation Date
After July 1, 2014
Percent Credit
40%
Percent Credit x Impervious
Area (SF) Treated
7,980 * 40% = 3,192
Impervious Area
Reduction (SF)
3,192
Adjusted Stormwater Utility Fee Calculation for COD and Voluntary Facilities
Adjusted Impervious Area (SF): 15,120 (pre credit) – 2,475 (voluntary reduction) – 3,192 (COD
reduction) = 9,453
Adjusted Billing Units: 9,435 / 500 = 18.9 = 19 BUs
Adjusted Annual Stormwater Utility Fee: 19 BU x $1.20 x 12 = $273.60 ($172.80 Fee Reduction)
Stormwater Utility Credits Manual – January 2014
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Credit Example 3
Voluntary Onsite and Offsite Stormwater Management Facility
Total Impervious Area = 15,120 SF
15,120 SF / 500 SF = 30.24
Property Billing Units (BU) = 31
Pre-Credit Annual Fee = (31 x $1.20
per BU x 12 months) = $446.40
Impervious Onsite Area Treated by
Voluntary Facility
(Parking Lot) = 4,340 SF
Impervious Offsite Area Treated by
Voluntary Facility
(Parking Lot) = 4,560 SF
Voluntary Onsite and Offsite Credit Example
Voluntary Facility
Installation Date
Onsite After
July 1, 2009
Offsite After
July 1, 2009
Percent Credit
100%
(see calculation below)
100%
(see calculation below)
Percent Credit x Impervious
Area (SF) Treated
Impervious Area
Reduction (SF)
4,340 x 100% = 4,340
4,340
4,560 x 100% = 4,560
4,560
Voluntary Credit Calculation (After 7/1/2009)
(A)
Facility Efficiency for Level 2 Bioretention (per Virginia BMP Clearinghouse) = 90%
(B)
Facility Efficiency of 90% / 100 x 1.76 = 1.584
(C)
1.584 – 0.264 = 1.32
(D)
1.32 / 0.016 = 82.5
(E)
40% + 82.5 = 122.5% = 100% Total Facility Credit
Adjusted Stormwater Utility Fee Calculation for COD and Voluntary Facilities
Adjusted Impervious Area (SF): 15,120 (pre credit) – 4,340 (voluntary onsite reduction) – 4,560
(voluntary offsite reduction) = 6,220
Adjusted Billing Units: 6,220 / 500 = 12.4 = 13 BUs
Adjusted Annual Stormwater Utility Fee: 13 BU x $1.20 x 12 = $187.20 ($259.20 Fee Reduction)
Stormwater Utility Credits Manual – January 2014
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How do I apply?
A Credit Application Form must be submitted and approved by the City to receive a credit. To
be eligible for a credit, a stormwater management facility must have an agreement in place that
will allow the City access to inspect the stormwater management facility. The following
documentation is required:
1. Credit Application Form – see back of this manual.
2. Drainage Area Map – show property lines, impervious areas, facility drainage area
boundaries, and the total impervious cover served
by the facility.
3. Facility Description – include the type of facility,
date of installation, and the percent pollutant
removal efficiency based on information from the
Virginia Stormwater BMP Clearinghouse or other
state approved guidance documents.
4. Operation and Maintenance Plan – provide a brief
summary of how the facility will be operated and
maintained to ensure it continues to function as
designed. Include an annual routine maintenance
schedule. Include any modifications or repairs that
have occurred from installation to the time of
application.
5. Photos – provide a date-stamped image or images
showing the facility within one month of the
application date.
6. Stormwater Facility Maintenance Agreement –
provide a copy of the agreement that allows the City access to the site.
7. Stormwater Management Facility Inspection Form – see back of this manual; the form
must be prepared by or under the guidance of a professional engineer, licensed landscape
architect, or other professional acceptable to the City. The form must verify the drainage
area map and state that the facility is functioning as designed and will be adequately
maintained.
Once a credit has been approved, the property owner will remain eligible for the credit as long as
all conditions of the maintenance agreement are met and the facility passes periodic inspections
by City staff. If the property owner fails to submit required documentation or correct
deficiencies within the time specified by City staff, the facility will no longer be eligible for
credit. If this occurs, the property owner will be required to reapply through the initial credit
process.
Stormwater Utility Credits Manual – January 2014
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Important Resources and Links
General Information and Assistance
 Charlottesville Water Resources Protection Program
www.charlottesville.org/wrpp

Virginia Department of Environmental Quality Stormwater Program
www.deq.virginia.gov/Programs/Water/StormwaterManagement.aspx
Stormwater Management Facility Standards
 Virginia Stormwater BMP Clearinghouse
http://vwrrc.vt.edu/swc

Recommendations of the Expert Panel to Define Removal Rates for Urban Stormwater
Retrofit Projects
http://chesapeakestormwater.net/bay-stormwater/baywide-stormwater-policy/urbanstormwater-workgroup/retrofits/
Stormwater Utility Credits Manual – January 2014
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Credit Application Form
Applicant Name:
Date:
Property Information:
Owner
Street
City, State, ZIP Code
Mailing Address: (if different from property address)
Street
City, State, ZIP Code
Email Address:
Phone Number:
Stormwater Management Facility Description
Include type of facility, date(s) of installation and pollutant removal efficiency from the Virginia BMP
Clearinghouse, Recommendations of the Expert Panel to Define Removal Rates for Urban Stormwater
Retrofit Projects, or other state-approved guidance documents (provide documentation to support the
determined pollutant removal efficiency). Attach additional information if necessary.
Total amount of impervious area to be subtracted from the fee calculation for the
property (provide the sum of all included Credit Calculation Forms):
The following supporting documentation and materials must accompany this application
Drainage Area Map
Operation and Maintenance Plan
Copy of Stormwater Facility Maintenance Agreement
Photograph of the Stormwater Management Facility – The photo should be no more than one
month old.
Stormwater Management Facility Inspection Form
Owner Certification and Inspection Agreement
I am the property owner or I am duly authorized to act on behalf of the property owner, I have
reviewed the information contained in this application and the supporting documentation, and to the
best of my knowledge believe that it is true and accurate.
I commit to maintaining the stormwater management facility in good working condition.
I authorize the City or its representative to enter on my property for the sole purpose of inspecting
the stormwater management facility.
I understand that if an inspection by the City indicates that the facility is not properly maintained,
that the facility will no longer be eligible for credit if deficiencies are not corrected within the timeframe provided by City staff.
_________________________________________
Signature
___________________________
Date
This form and all supporting documentation and materials should be submitted to:
City of Charlottesville
Water Resources Protection Program
305 4th St NW
Charlottesville, Virginia 22903
Internal Use Only:
Facility ID#
Review Date:
Reviewer:
Approval Date:
Notes/Conditions:
Credit Calculation Form
Stormwater Management Facility Description:
Property Information:
Owner
Street
City, State, ZIP Code
Complete one form for each stormwater facility on the property. A single facility may be built as a
condition of development but voluntarily sized to treat additional on-site or off-site impervious area
beyond minimum regulatory standards.
COD or Voluntary Credit
Fixed Percent
(A) Impervious Area Treated:
SF
(B) Percent Credit from Credit
Level Table:
%
Voluntary Credit
On-Site – Variable Percent
(A) Impervious Area Treated:
Voluntary Credit
Off-Site – Variable Percent
(A) Impervious Area Treated:
SF
(B) Percent Credit from Credit
Level Table or Voluntary
Facilities Calculator:
SF
(B) Percent Credit from Credit
Level Table or Voluntary
Facilities Calculator:
%
(C) Impervious Area Credit =
(A) x (B) =
SF
(C) Impervious Area Credit =
(A) x (B) =
%
(C) Impervious Area Credit =
(A) x (B) =
SF
SF
Add Columns 1, 2, and 3 for the Total Impervious Area Credit:
Credit Calculator for Post-July 1, 2009 Voluntary Water Quality Facilities
(a)
Facility Efficiency Must be 15% or Greater
(b)
Facility Efficiency of
(c)
(b) – (0.264) =
(d)
(c) / 0.016 =
(e)
40% + (d) =
/ 100 * 1.76 =
Percent Total Facility Credit
See the Virginia BMP Clearinghouse, Recommendations of the Expert Panel to Define Removal Rates for Urban
Stormwater Retrofit Projects, or other state-approved guidance document for pollutant removal rates.
SF
Stormwater Management Facility
Inspection Form
Applicant Name:
Date:
Property Information:
Owner
Street
City, State, ZIP Code
Stormwater Management Facility Description:
Impervious Area Draining to the Facility:
Year Built:
SF
City ID (if known):
General Condition:
Is the primary outfall pipe/ ditch clear and functioning?
Are the inflow pipes/ ditches clear and functioning?
Is the water quality pool at the correct height (if present)?
Are water quality pool control weirs, pipes, etc. working properly (if present)?
Are emergency overflow devices clear and functional (if present)?
Is the structure clear of sediment?
Is the structure clear of trash?
Is vegetation being managed in a manner appropriate to the facility?
Yes
No
N/A
Certification
This certification must be made by a licensed professional engineer, landscape architect, or other
professional accepted by the City.
Based on a visual survey of the above facility conducted on __________________, I certify that the
facility is currently functioning as designed.
I certify that the total impervious cover served by the facility and the accompanying Drainage Area
Map are true and accurate.
______________________________________
Printed Name
________________________________
Date
______________________________________
Signature
________________________________
Qualification
______________________________________
Address
________________________________
Phone
______________________________________
Email